Bonnevie-Ullrich syndrome; Gonadal dysgenesis; Monosomy X; XO
Turner syndrome is a rare genetic condition in which a female does not have the usual pair of 2 X chromosomes.
The typical amount of human chromosomes is 46. Chromosomes contain all of your genes and DNA, the building blocks of the body. Two of these chromosomes, the sex chromosomes, determine if you become a boy or a girl.
In Turner syndrome, cells are missing all or part of an X chromosome. The condition only occurs in females. Most commonly, a female with Turner syndrome has only 1 X chromosome. Others may have 2 X chromosomes, but one of them is incomplete. Sometimes, a female has some cells with 2 X chromosomes, but other cells have only 1.
Possible findings of the head and neck include:
Other findings may include:
A child with Turner syndrome is much shorter than children who are the same age and sex. This is called short stature. This problem may not be noticed in girls before age 11.
Puberty may be absent or not complete. If puberty occurs, it most often begins at the normal age. After the age of puberty, unless treated with female hormones, these findings may be present:
Sometimes, the diagnosis of Turner syndrome may not be made until an adult. It may be discovered because a woman has very light or no menstrual periods and problems becoming pregnant.
Turner syndrome can be diagnosed at any stage of life.
It may be diagnosed before birth if:
The health care provider will perform a physical exam and look for signs of poor development. Infants with Turner syndrome often have swollen hands and feet.
The following tests may be performed:
Turner syndrome may also change estrogen levels in the blood and urine.
Growth hormone may help a child with Turner syndrome grow taller.
Estrogen and other hormones are often started when the girl is 12 or 13 years old.
Women with Turner syndrome who wish to become pregnant may consider using a donor egg.
Women with Turner syndrome may need care or monitoring for the following health problems:
Other issues may include:
Those with Turner syndrome can have a normal life when carefully monitored by their provider.
There is no known way to prevent Turner syndrome.
Bacino CA, Lee B. Sex chromosome aneuploidy. In: Kliegman RM, Stanton BF, St Geme JW, Schor N, eds. Nelson Textbook of Pediatrics. 20th ed. Philadelphia, PA: Elsevier; 2016:chap 81.
Saenger P, Bondy CA. Turner syndrome. In: Sperling MA, ed. Pediatric Endocrinology. 4th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 16.
Last reviewed on: 10/27/2015
Reviewed by: Chad Haldeman-Englert, MD, FACMG, Fullerton Genetics Center, Asheville, NC. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.